Internal combustion engines are subject to deviations in pilot mixture controlling due to the interaction of tolerances specific to individual system components such as, for example, injection valves, load sensors, etc. When mixture controlling has been activated by the lambda control and through mixture controlling while the internal combustion engine is at its operating temperature, the system tolerance will be minimized and subsequently contribute only slightly to the internal combustion engine's emission characteristics. Only immediately after the internal combustion engine starts do the system tolerances have a direct impact on its emission characteristics.